<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>

</body>
<script>
    const user1 = {
        name: 'zhangsan',
        age: 19
    }
    let name = 'lisi';
    let age = 20;
    const user2 = {
        name: name,
        age: age,
        sayHello: function() {
            console.log('hello');
        }
    }
    const user3 = {
        name,
        age,
        sayHello() {
            console.log('hello3');
        }

    }
    user2.sayHello();
    console.log(user3);
    user3.sayHello();
</script>

</html>